1. Field of the Invention
This invention generally relates to a backlight module and a display device using the same. More particularly, this invention relates to a backlight module capable of reducing interference to an electromagnetic touch panel and a display device using the same.
2. Description of the Prior Art
As the competitiveness of electronic products becomes more and more drastic, the design of various electronic products is much more diverse. Apart from the improvement in functions, product appearance and user interface are also important concerns of design. In the design of electronic products, the use of touch display device has become an important part. The touch display device on one hand can provide the display function and on the other hand, can serve as the interface for communication with users.
Conventional touch display devices mostly adopt the combination of a touch panel and a display panel. The touch panels are typically classified into resistance type, capacitive type, and electromagnetic type based on their operational principles. Specifically, the electromagnetic touch panel has better durability, high sensitivity, and Z-axis sensing ability; therefore, the electromagnetic touch panel is popular in the touch panel market.
FIG. 1 is a schematic view of a conventional electromagnetic touch display device. The electromagnetic touch display device includes a liquid crystal display panel 10, an electromagnetic touch panel 20, and a backlight module 30. The electromagnetic touch panel 20 is disposed on the back side of the liquid crystal display panel 10 and the backlight module 30, i.e. not on the image display side. The backlight module 30 is disposed on the back side of the liquid crystal display panel 10 to provide the liquid crystal display panel 10 with required light for displaying images. The backlight module 30 includes a light source structure consisting of a flexible circuit board 31 and light emitting diodes 33. Since the light source structure is connected to a signal source 50 disposed outside the backlight module 30 by means of the flexible circuit board 31, the flexible circuit board 31 has to go across the area between the electromagnetic touch panel 20 and the display panel 10. However, in the conventional design, the flexible circuit board 31 is disposed with metal wires which interfere with the touch sensing operation of the electromagnetic touch panel 20 and accordingly impair the sensing accuracy.